Cheltenham Town paid a high price for their profligacy in front of goal at Vale Park, suffering their first league defeat on their travels this evening.
In fact they had yet to concede a goal and things looked so promising after Andy Williams handed his side a well deserved lead three minutes after the break, his fourth goal of the campaign.
Up to that point Michael Duff’s side had produced a string of fantastic chances, consigning their hosts into long spells of defending.
But the goal proved to be a turning point, only in favour of the Valiants who went on to produce two of their own within 20 minutes to seal the come-from-behind win.
The manager was frustrated with his side’s lack of incision after the game.
“It was a soft performance,” he said.
“That’s the word. We weren’t clinical enough and we should have been out of sight after an hour.
“We went 1-0 with a really good goal and then gave a really poor one away. There’s a lack of communication and then we invited them on to us.
“It feels like we haven’t got out of second gear again so we need to be more ruthless with each other. They are a great group and a joy to work but I am angry tonight. It’s frustrating because I think the league’s there for someone to go and take.”
Duff’s selection was once again disrupted by injuries after Matty Blair picked up a groin problem in the game against Mansfield Town four days ago.
In came Conor Thomas to deputise at right-wing back, while Williams came into the attack at the expense of Reuben Reid.
The Robins dominated the opening 50 minutes or so of the contest, creating chance after chance.
Alfie May was presented with the first on the night but his volley flew over the bar.
Five minutes later was then an incredible passage of play which saw Williams call Scott Brown into a smart save before the former Robin denied Sang with a sprawling block. Williams then headed against the bar before Liam Sercombe was put through, but the midfielder pushed his effort wide of the right post.
May fashioned another chance moments later, dragging his effort wide from 20 yards while Williams narrowly missed the target from distance ten minutes before the break.
At the other end a moment of brilliance handed David Amoo a chance on the stroke of half-time, but it flew an inch over.
The Robins finally got their reward three minutes after the restart through a neatly worked move down the left, started by Hussey who flicked a ball into the path of Boyle. The centre half swept across a ball, flicked on by May and met by Williams at the far post to head home.
But the lead lasted just four minutes, Leon Legge meeting David Worrall’s ball corner from the right with a free header.
Brown was then alert to a fine Chris Hussey effort to produce a fingertip save and concede a corner from the right. Hussey picked it up, sending it to the back post but Boyle glanced his header wide.
The hosts were in front 22 minutes from time when Worrall picked up the ball and cut inside Charlie Raglan before firing past Griffiths from 25 yards to hand his side the lead as the game drew to a close.
There was a late chance for substitute Tom Pope, but his downward header came back off the post and cleared.
PORT VALE (4-3-3): Brown; Clark, Legge (c), Smith, Montano; Amoo, Joyce, Conlon; Burgess, Robinson (Pope 63), Worrall. Subs not used: Cullen, Brisley, Whitehead, Rodney, Fitzpatrick, Visser.
CHELTENHAM TOWN (3-5-2): Griffiths; Raglan, Tozer (c), Boyle; Thomas, Sang (Addai 76), Clements (Reid 83), Sercombe, Hussey; Williams, May. Subs not used: Harris (Gk), Bowry, Freestone, Horton, Chapman.
REFEREE: D Whitestone